1. Field of the Invention
The present invention relates generally to the field of audio electronics, and more particularly, to audio cables.
2. Description of the Related Art
Heretofore, there have been two general classes of audio cablesxe2x80x94shielded or non-shielded. There are known advantages and disadvantages to both classes.
It is commonly known that single or multiple shields lower RF and EM interference in audio cables. When shields run parallel to the conductors, a synthesized proximity effect is created that is a spectral detriment to the normal flow of electrons through the conductors. This negatively effects the frequency balance.
It is known by the inventor that the capacitance and inductance of unshielded conductors in an audio cable negatively impacts the audio characteristics of the cable. One possible method used to reduce capacitance is to magnetically shield the conductors from each other for the entire length of the cable. Unfortunately, the use of a continuous shield between the two conductors increases inductance that negatively impacts audio characteristics of the cable.
What is needed is an improved audio cable with shielded conductors that have relatively low capacitance and low inductance, and that are definitively defined rather than mathematically averaged over the length of the cable.
It is an object of the present invention to provide an improved audio cable that uses shielded conductors.
It is another object of the invention to provide such an audio cable that has relatively low capacitance and low inductance.
It is a further object of the present invention to provide such an audio cable wherein the capacitance and inductance are definitively defined rather than mathematically determined by averaging the capacitance and inductance over the entire length of the cable.
These and other objects of the present invention are met by an improved audio cable disclosed herein comprising at least one pair of first and second conductors that extend continuously along the cable. Located between the two conductors is a shielding means that extends substantially the entire length of the cable. Formed in the shielding means is at least one small opening, hereinafter called a lens, which exposes the magnetic fields of the two conductors to each other. By continuously shielding the two conductors and then briefly exposing their magnetic fields of the conductors to each other, both the capacitance and inductance of the conductors are reduced thereby improving their overall audio characteristics of the cable. A suitable connector plug is attached to the opposite ends of the conductors that enables the ends of the cable to connect to the audio equipment.
In the first and second embodiments, the shielding means is a straight or spiral-shaped lead shielding member that extends the entire length of the cable. The conductors are spaced apart and located on opposite sides of the shielding member. Two lenses are formed near the opposites ends of the shielding member or one lens is formed at the center axis of the shielding member. The lenses are sufficient in size and shape to enable the conductors to be placed in close proximity or touch. In the preferred embodiment, the conductors extend through the lens and travel along the opposite sides of the shielding member. An optional outer shielding member may be placed around the conductors and lenses only or places over the entire length conductors to reduce outside interference.
In a third embodiment, the shielding means is a tubular member made of shielding material with a cathode conductor located inside and an anode conductor wrapped spirally around the tubular member. Extending from the end of the tubular member is a flat shielding member with a hole formed therein. During assembly, the conductors exit the tubular member on opposite sides of the flat shielding member and then extend through the hole and contact. The ends of the conductors then connect to a standard plug.
In yet another embodiment, the shielding means are two parallel tubular members made of shielding material that contain either a cathode conductor or an anode conductor. The ends of the tubular members terminate at the same location. A flat shielding member similar to the flat shielding member used with the third embodiment is placed between the two tubular members. When the conductors exit the tubular members, they travel on opposite sides of the flat shielding member and extend through the lens.
With each embodiment mentioned above, the length of the cathode and anode conductors may be manufactured in equal lengths.